op {
  graph_op_name: "IteratorGetNextSync"
  summary: "Gets the next output from the given iterator."
  description: <<END
This operation is a synchronous version IteratorGetNext. It should only be used
in situations where the iterator does not block the calling thread, or where
the calling thread is not a member of the thread pool used to execute parallel
operations (e.g. in eager mode).
END
}
